Electromechanical action for musical instruments.



F. B. LITTLE.

ELECTROMECHANICAL- ACTION FOR MUSICAL INSTRUMENTS. APPLI( IATION FILEDFEB- 25, 1916.

1,228,223. Patented May 29, 1917.

Specification of Letters Patent,

Patented May 29, 1917.

Application filed February 25, 1916. Serial No. 80,328.

To all whom it may aoncem:

Be it known that I, FREDERICK B. Lrrnn, citizen of the United States,residing at Chicago, in the county of Cook and State of llinois, haveinvented a certain new and useful Improvement in Actions for MusicalInstruments, of which the following is a full, clear, concise, and ex- Iact description, reference accompan g drawings, this specifi dz t tion.1

My invention relates to musical instruments of the percussion type andhas for its object the construction of an improved electro-magneticaction whereby the sound producing elements of the instrument ma beimpinged upon by hammers with blows of 'table force and in such mannerthat the hammers will not dampen the vibrations they set up in the soundproducing elements. practising my invention I employ an electro-magnetfor each action, the armature of the magnet carrying a hammer and also aswitch actuating element for opening the circuit of the magnet when thehammer has been moved a predetermined distance toward the soundproducing element it is to strike being bad to the forming a part ofwhereby the circuit of the magnet is opened erally on line 1 1 of Fig.

before the hammer completes its travel, momentum being relied upon tocomplete the hammer travel. A spring is employed against the force ofwhich the magnet moves the hammer and against the force of which thehammer is moved by momentum when the circuit of the magnet is opened,the spring serving to restore the hammer after it has struck so that thehammer will not linger to dampen the vibrations set up in the vibratingelement it has struck.

I will explain my invention fully by reference to the accompanyingdrawing showing the preferred embodiment thereof and in which Figure 1is a view taken gen 2, the circuit arrangement of the magnet being alsodiagrammatically indicated in this gure; Fig. 2 is a front view of thestructure shown in Fig. 1, a cap being shown in section at the upper endof the gure to reveal parts that it would hide; Fig. 3 is a perspectiveview of the switching and armature mechanism which I prefer to employ;Fig. 4 is an end elevation of the magnet structure shown in Figs. 1 and2, the hammer being removed while the casing is shown in cross sectionon Electromechanical I my mventlon resonator 2 as at 4 to and betweenthe lindrica'l casing 7 line 4 4 of Fig. 1; and Fig. 5 is a view takenat right angles to the part shown in Fig. 4. Like parts are indicated bysimilar characters of reference throughout the different figures.

The sound producing elements to which is adapted may be of any suitablenature, the sound producing element illustrated in the-drawing being inthe form bar 1 located in front of a will be well understood by thosefamiliar with. the art. A hammer 3 for striking the bar 1 is pivotallymounted ears 5 projecting from a bracket 6 that is attached to the cybythe screws 8. Nuts 9 are threaded upon the free ends of the hammer stem10, the hammer ball 3 being secured between the nuts and beingadjustable longitudinally of the stemflby reason thereof. The other endof the hammer stem projects from the armature 11, which is preferablycircular, that carries the bar 12 by means of which the armature, aswell as the hammer, is pivoted at 4. The bracket 6 carries an arm 13that is insulated there from, a screw; 14 having threaded connectionwith this arm. A binding nut 15 is provided upon the screw for thepurpose of engagin a circuit terminal therebetween and the %ar 13whereby the screw is brought into electrical connection with suchterminal. A terminal contact 16 is carried by the screw 14, this contactbeing compleof a vibrating mental to a terminal contact 17 carried uponthe same. The arm 19, obviously, is insuand thenut engaging lated fromthe-arm 13 since the latter arm is insulated from the bracket 6. The arm19, however, may be electrically connected with the bracket and themetallic parts upon the bracket. The magnet winding 21 of each action isincluded in a circuit traceable from the battery 22, the circuit closinginstrument playing key 23, the contact screw 14 and the contact 16carriedupon one end thereof, the contact 17 and the leaf spring 18carrying this contact, thence to the winding 21 back to the battery.Whenever the switch 23 is' closed the winding 21 is energized and thearmature 11' of the magnet is attracted to move the hammer to--magnetically ward the sounding bar, the magnet being pulled until theinsulating block 24 carried by the bight of the stirrup 25 engages thespring 18 that passes through the stirrup, it being observed that thestirrup moves with the armature as it is clamped between the armatureand the bar 12. The engagement of the switch actuator 24 with the switchspring 18 occurs before the hammer 9 strikes the bar 1 and serves tobreak the circuit of the magnet at this time whereby the hammercompletes its movement by momentum, it being thereby prevented fromdampening the vibrations it sets up as it is instantly removed fromengagement with the bar by the retractile spring- 26. This spring notonly serves to retract the armature and the hammer but also serves todampen the movement of the armature when the armature is magneticallyattracted whereby the momentum imparted to the hammer is properlyreduced. The magnet winding 21 is set into an iron cup 21 that isprovided to make the magnet ironclad. The iron core 27 is attached tothe end wall of this cup. The armature at the other end of thecup-shaped casing is opposed to the core and the rim'of the casing, themagnet structure illustrated being highly efficient as there are nowasteful air gaps to be threaded by magnetic flux. The

spool upon which the winding is disposed is preferably made of brass,the core 27 passin through the spool sleeve 28 while the en walls 29 ofthe spool define the winding space. A piece of felt 30 may be providedto prevent the armature from sticking and to prevent it from makingnoise when the hammer strikes.

Each switch 23 is individual to one magnet, it being understood that thedifferent magnets are associated with different sounding bars that arearranged to produce the sounds of a musical scale. Taps 31 indicate theconductors that lead from the battery 22' to other switches 23 and taps32 indicate conductors that lead from the other side of battery 22 toother magnet windings 21, though other circuit arrangement may beemployed. The battery itself is included in a conductor that is commonto all of the magnets, this conductor also including a switch 33 whichmay be thrown into one position when all of the magnets are to beexcluded from circuit, termediate position when the normal battery 22 isto be included in circuit; and which may have a third position when thewhich may have an 1nextra battery 34 is to be included in series withthe battery 22 to increase the voltage and cause the stronger operationof the hammer, the switch 33 thus constituting a modulating switch aswell as a circuit opening and closing switch.

The insulating block 24 is desirably made of cushioning material andalso extends outwardly so as to engage the arm acting as a rigid backstop when the armature is retracted, the co tact actuator of which theinsulating block 24 forms a part being also employed as a means to limitthe extent to which the armature may be retracted. The stirrup thatsupports the block is preferably resilient as well as the block 24 sothat the armature is not violently arrested in its restorin .movement.

While I have herein shown and particularly described the preferredembodiment of my invention I do not wish to be limited to the precisedetails of construction shown as changes may readily be made withoutdeparting from the spirit of my invention, but having thus described myinvention I claim as new and desire to secure by Letters Patent thefollowing An electro-mechanical action for percussion musicalinstruments including an electro-magnet; a hammer carried by thearmature of the magnet; a pair of contacts in the magnet circuit, one ofthese contacts having a spring support to enable it to be moved towardand from the other; a mounting for these contacts that is apart from themagnet armature; a contact actuator car-' ried by the armature andarranged to move said spring su port to exclude the magnet from circuitefore the magnetically attracted armature has completed its range ofmovement whereby the hammer will continue in movement of momentum; and aspring for restoring the armature and hammer and against the force ofwhich spring the armature is magnetically attracted, the aforesaidmounting constituting a back stop engaged by said contact actuator whenthe armature 1S restored to limit the restoring movement of the armatureefiected by the armature restoring spring.

In witness whereof, I ereunto subscribe I1I1i name this 17th day ofFebruary A.

FREDERICK B. LITTLE.

Witnesses:

G. L. Green, -ETTA L. W.

